I heard that the boot camp seen in FMJ was relatively new, a result of draftees refusing to fight on the battlefield during WWII. I heard something like over a half of US and British troops refused to even fire their guns during WWII. They basically hid in the fetal position.

You need to clear you Google search history. In fact, just go ahead and exchange your modem.

I guess it was only US troops. It makes sense though. They had the least incentive of any country to fight. Nobody was going to shoot them in the head for failing to engage. I don't remember US soldiers locking arms and walking mine fields with machine guns at their back.

I'm not researched on the topic, but surely something was responsible for the change in military boot camp. It would be interesting to hear about it from a military historian.